Ornithol Sci 9: 131–134 (2010)

ORIGINAL ARTICLE First Breeding Record of Japanese Night goisagi in Korea

Hongshik OH1,#, Youngho KIM1 and Namkyu KIM2

1 Department of Science Education, Jeju National University, Jeju 690–756, Republic of Korea 2 Korea International Photo Movie Interchange Association, IdoI-dong, Jeju-si, Jeju Special Self-governing Province 690–120, Republic of Korea

Abstract We studied the breeding biology of the Japanese Gorsachius ORNITHOLOGICAL goisagi from 21 June to 2 August 2009. This species was previously considered an SCIENCE endangered endemic breeding species of southern only, but was found breeding © The Ornithological Society in a valley at the bottom of Mt. Halla at Ara-dong, Jeju City, the southernmost island of Japan 2010 of Korea. This marks the first record of this species ever to be found breeding in Korea. The forested area consisted predominantly of plants such as Morus bombycis, Cryptomeria japonica, Styrax japonica, Orixa japonica, Viburnum dilatatum, and Lindera erythrocarpa. Materials for the nest were largely M. bombycis, followed by S. japonica, C. japonica, and so forth. There were three eggs in the clutch, and the brooding period lasted for 42 days. A close look into the pellets demonstrated that their main prey items were , snails, and cicadas. The results of this study represent valuable data, allowing for the mapping out of new methods for managing Gorsachius goisagis, a species currently on the brink of extinction.

Key words Breeding record, Conservation, Gorsachius goisagi, , Jeju Island

The Japanese Night Heron Gorsachius goisagi a Environment of the Republic of Korea as a Class II species belonging to the Ardeidae family in the Ci- endangered species and is now under close protec- coniiformes order, resembles other night , but tion. is reddish-brown all over with blackish-brown stripes Japanese Night Herons have previously been re- down the middle of the front of its throat. It has a ported from several Korean sites including Busan and short, thick bill and an area of yellow skin in the front Jeju Island (Lee et al. 2000). In and around Jeju Is- of the eyes. Although it normally walks silently on land, one individual was detected at Sagye-ri, An- the ground, its wings make an audible fluttering noise deok-myeon, on 5 April 1980; one individual was at when it takes off (Brazil 1991, 2009; Park 1998; Yongsu-ri, Hangyeong-myeon, on 8 May 1990; one Kushlan & Hafner 2000; Lee et al. 2000). individual was at Seogwang-ri, Andeok-myeon, on Long considered an endemic breeding species only 17 May 1994; and one corpse was found at Seonheul- to southern Japan (Kushlan & Hancock 2005), the ri, Jocheon-eup, on 14 June 1997 (Park 1998). In this Japanese Night Heron is known to winter in areas paper we report the first record of successful breeding such as Southern , , and the in Korea. This study aims to provide the facts and fig- (Kushlan & Hafner 2000; Lee et al. 2000). Fewer ures necessary to preserve and protect these individ- than 1,000 individuals now reportedly exist, and as a ual and their habitats by reporting on their ob- result the species has been designated as ‘endan- served breeding processes. gered’ by the International Union for Conservation of Nature and Natural Resources (BirdLife International STUDY AREA AND METHODS 2007). It has also been designated by the Ministry of The breeding site was amongst bushes in a valley (Received 20 January 2010; Accepted 1 September 2010) at the bottom of Mt. Halla at Ara-dong, Jeju City, Jeju # Corresponding author, E-mail: [email protected] Special Self-Governing Province (33°2616.76N,

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Fig. 1. Breeding site (Circle) of Japanese Night Heron near Ara-dong on Jeju Island in the Republic of Korea.

126°3453.21E, 475 m above sea level, Fig. 1), or from any Ixobrychus or Butorides bittern species. where humidity remained at 70% or above. The flora The nest was constructed of tree branches available of the area and its vicinity consisted of plants such as from the surrounding vegetation, which included S. Morus bombycis, Cryptomeria japonica, Styrax japonica, C. japonica and M. bombycis trees, which japonica, Orixa japonica, Viburnum dilatatum, and made up the bulk of the materials. When first located, Lindera erythrocarpa. Our observations were con- the nest contained three white eggs, one of which ducted with the aid of a pair of binoculars (Brunton hatched on 22 June, with another egg successfully 1032), and pictures were obtained using a video hatching the following day. The other egg was ob- camera and a still camera (Nikon D3, 80–200 mm). served until 31 July, and was thereafter observed no Pellets were collected from around the nest and a an- more, as the parents apparently abandoned it. The alyzed in the laboratory to determine prey items. growing process was observed every 2–3 days, as is Once the nest had been abandoned it was also taken shown in Fig. 3. It was also noted that the birds left to the laboratory and the materials utilized in its con- the nest on 1 August, or 42 days after hatching. struction was analyzed. The parents left the nest at 0800, returning home 7–9 hours later, with long intervals between feeding RESULTS AND DISCUSSION times. When there were signs of human presence nearby, the birds were extremely vigilant, sometimes While studying breeding ecology in the vicin- returning to the nest only in the evening. It was also ity of the valley by Ara-dong, Jeju City, on 17 June noted that over the 20-day hatching period, they re- 2009, we observed a Japanese Night Heron sitting in turned to the nest once or twice daily, 2–3 times after a nest on the branch (7 meters high) of a Mulberry 25 days of hatching, feeding their chicks 5–6 times tree M. bombycis, approximately 8 meters tall in the daily after 30 days of hatching, and feeding their forest (Fig. 2). When it was first observed, the color chicks twice daily after 35 days of hatching. of the crown was noted as chestnut, and the part While feeding the chicks, the parents ruffled out around the head was without the crest, the part be- their plumes, puts the bill deep into the mouth of the tween the eyes and the beak assumed the yellow. And chick, and regurgitated food. As the food was imme- the anterior ends of the remiges were without white diately swallowed it was not possible to determine tips, making it readily distinguishable from the simi- what was fed to the chicks directly. However, a closer lar Gorsachius melanolophus look into the pellets confirmed that the prey primarily

132 First Breeding Record of Japanese Night Heron in Korea

Fig. 2. Adult Japanese Night Herons at their nest.

Fig. 3. The growth stages of two young Japanese Night Herons (22 June to 1 August 2009).

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Table 1. Composition of prey species in pellets of Japanese been observed there during their breeding season, and Night Herons (Number of pellets18). the vegetation and feeding resources there are similar to those observed in Japan. Kushlan & Hafner (2000) Fragment Food Scientific and Kawakami & Higuchi (2003) have reported that number items name Japanese Night Heron numbers have dwindled due to of preys habitat loss, particularly of hillside and mountain Snails forests as a result of development projects. It is as- Basomatophora/Baradybaenidae sumed that the individuals breeding on Jeju Island Nesiohelix samarangae 6 may have been displaced there from lost breeding Snails sp. 2 sites in Japan. This is most welcome from the per- spectives of the expansion of the breeding range and Earthworms the protection of breeding sites. Administrative and Lumbriculida Lumbriculida sp. 16 financial support is urgently needed for future studies in order to accumulate the necessary data for the preservation of the population of the Japanese Night Hemiptera/Cicadidae Heron in the future, and to prevent its extinction. Graptopsaltria nigrofuscata (imago) 6 Gryptotympana dubia (larva) 2 Coleoptera/Carabidae ACKNOWLEDGMENTS Pterostichus sp. (imago) 1 This work was supported by a research grant from the Nicrophorus sp. (imago) 1 Chuongbong Academic Research Fund of Jeju National Uni- Insects sp. (imago) 2 versity.

Table 2. Measurements of Japanese Night Herons in mm REFERENCES (N2). BirdLife International (2007) Threatened Birds of : Total No Ring No Wing Tail Tarsus Bill the BirdLife International Red Data Book. Cam- Length bridge, UK. Brazil M (1991) The birds of Japan. Christopher Helm 1 090-01051 177 92 71.1 35.8 400 2 090-01052 181 91 67.9 36.5 396 Ltd., London. Brazil M (2009) Birds of East Asia. Princeton Univer- sity Press, Princeton and Oxford. included earthworms, snails, and cicadas (Table 1). Kawakami K & Higuchi H (2003) Population trend esti- Such findings that Japanese Night Herons have a spe- mation of three threatened bird species in Japanese cial liking for snails, earthworms, and insects are sim- rural forests: the Japanese Night Heron Gordachius ilar to the results of surveys conducted in Japan, as goisagi, Goshawk Accipiter gentilis and Grey-faced clarified by the Japanese findings regarding the diet Buzzard Butastur indicus. J Yamashina Inst Ornithol 35: 19–29. of Japanese Night Herons (Kawakami et al. 2005). Kawakami K (2002) The possibility of extinction of Measurement of the chicks (Table 2) on 20 July, or Japanese Night Heron. Wild birds 67: 13–15. (in 30 days of hatching, after capturing one to attach a Japanese) metal ring on the ground, shows that it had grown up Kawakami K, Uchida H & Fujita H (2005) Diet of the to adulthood in size. The bill turned out to be small, Japanese Night Heron Gorsachius goisagi in Japan. as compared with those of other Herons (Kawakami Ornithol Sci 4: 173–177. 2002), presumably because they found their prey Kushlan JA & Hafner H (2000) Heron Conservation. down in the soil or among the flora, unlike other Academic Press, New York. Herons addressed in diet studies conducted in four Kushlan JA & Hancock JA(2005) The Herons. Oxford areas, Hachioji, Akiruno, Saitama and Hiroshima, University Press, New York. making it short morphologically in relation with its Lee WS, Koo TH & Park JY (2000) A field guide to the prey. birds of Korea. LG Evergreen Foundation, Seoul. It is hoped that Japanese Night Herons will con- Park HS (1998) The birds of Cheju Island. Jeju National tinue to breed on Jeju Island, as they have recently University Press, Jeju. (in Korean)

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